Chaos-based Image Encryption Scheme Research Articles

An image encryption scheme based on the four-dimensional chaotic system and the mealy finite state machine

This paper proposes a four-dimensional hyperchaotic system to overcome the defect of weak encryption effect due to the simple complexity of low-dimensional chaotic systems in chaos-based image encryption schemes, which is verified to have better chaotic properties by dynamics analysis, sensitivity analysis, and randomness test. In addition, this paper proposes an image encryption scheme by combining the proposed chaotic system with the Mealy finite state machine (MFSM) to overcome the problem that some schemes are not resistant to statistical analysis. Firstly, the chaotic sequence is applied in the Knuth-Durstenfeld shuffling method to scramble the original image efficiently; secondly, according to the different information contained in the bit-plane, the pixel is decomposed and cyclically shifted at the bit level to achieve bit-level scrambling and diffusion; thirdly, the chaotic sequence is applied to select the rules for DNA encoding, and the diffusion process is achieved by Mealy finite state machine transformation; lastly, decoding the diffused image by selecting DNA rules randomly to get cipher image. This paper gives the experimental results, demonstrating that the scheme is highly secure. It can improve the encryption scheme’s sensitivity to plaintext and resist attacks such as differential attacks and select attacks.

A Lightweight Image Encryption Scheme Using DNA Coding and Chaos

Protecting transmitted multimedia data such as images is a significant concern. This work proposes an encryption algorithm for greyscale images using a Pseudo-Random Number Generator (PRNG), DNA coding, and pixel sum. The proposed approach is implemented on a Genesys 2 FPGA using minimal hardware resources and can operate at a maximum frequency of 110.8 MHz. In addition, several performance evaluation tests are conducted for multiple images, including statistical analysis of the encrypted image, keyspace analysis, and differential attack analysis. The system is compared to recent works with respect to encryption quality and used hardware resources. The proposed scheme outperformed recent chaos-based image encryption schemes.

Encipher GAN: An End-to-End Color Image Encryption System Using a Deep Generative Model

Chaos-based image encryption schemes are applied widely for their cryptographic properties. However, chaos and cryptographic relations remain a challenge. The chaotic systems are defined on the set of real numbers and then normalized to a small group of integers in the range 0–255, which affects the security of such cryptosystems. This paper proposes an image encryption system developed using deep learning to realize the secure and efficient transmission of medical images over an insecure network. The non-linearity introduced with deep learning makes the encryption system secure against plaintext attacks. Another limiting factor for applying deep learning in this area is the quality of the recovered image. The application of an appropriate loss function further improves the quality of the recovered image. The loss function employs the structure similarity index metric (SSIM) to train the encryption/decryption network to achieve the desired output. This loss function helped to generate cipher images similar to the target cipher images and recovered images similar to the originals concerning structure, luminance and contrast. The images recovered through the proposed decryption scheme were high-quality, which was further justified by their PSNR values. Security analysis and its results explain that the proposed model provides security against statistical and differential attacks. Comparative analysis justified the robustness of the proposed encryption system.

A Proposal of a New Chaotic Map for Application in the Image Encryption Domain

Several chaos-based image encryption schemes have been proposed in the last decade. Each encryption scheme has pros and cons regarding its speed, complexity, and security. This paper proposes a new chaotic map called Power-Chaotic Map (PCM). Characteristics of the proposed PCM, such as chaotic behaviour, randomness, sensitivity, and s-unimodality, are investigated. As an application of the proposed chaotic map, an image encryption scheme is proposed to encrypt greyscale and text images. The proposed three-phase image encryption scheme performs a series of substitution and permutation operations. The Pixel-Level phase utilises the PCM’s generated keystreams to perform the substitution operation of image pixels. The Row-Level phase permutates, via a proposed pseudorandom number generator, pixel locations of each row and then shuffles row locations. Finally, the Column-Level phase performs a substitution operation on pixels of each column. Performance of the proposed PCM-based image encryption scheme is investigated through histogram analysis, statistical correlation analysis, key sensitivity, encryption performance of text images, and permutation and substitution properties. Experimental results indicate that the PCM has a wider range of chaotic behaviour than well-known one-dimensional maps, meets the s-unimodality property, has high sensitivity, and generates keystreams with random-like behaviour. Furthermore, results indicate that the PCM-based image encryption scheme provides high encryption security for text images, high key sensitivity, immunity against brute-force attacks, strong statistical correlation results, strong encryption performance, and low computational complexity.

Security and Performance Analysis of Chaos-based Image Encryption Schemes

Security and Performance Analysis of Chaos-based Image Encryption Schemes

A chaos-based image compression and encryption scheme using fractal coding and adaptive-thresholding sparsification

With the wide application of digital images in the network, the problems of information security and transmission efficiency need to be solved urgently. Fractal encoding as an efficient compression method, its security is not guaranteed. To solve these problems, this paper proposes a new image compression and encryption scheme based on chaotic map and frequency division joint compression coding, which uses the combination of fractal encoding and adaptive-thresholding sparsification to compress images. Arnold scrambling and chaos-based plane scrambling diffusion are embedded in two compression processes respectively. In addition, an efficient encryption algorithm is designed based on the coupling-enhanced chaotic map, which encrypt the compressed data as a whole through simultaneous scrambling of parent blocks and sub-blocks and zigzag round-trip diffusion. The simulation results demonstrate that the proposed image compression and encryption scheme is suitable for gray and color images, and can achieve higher compression ratio and improve the efficiency of fractal compression. The designed encryption algorithm is reliable, and more efficient than several advanced image encryption schemes.

A Chaos-Based Image Encryption Scheme Using the Hamming Distance and DNA Sequence Operation

In this study, we introduced a new memristive chaotic system with the rich dynamic behavior, and then we proposed a chaotic-based image encryption scheme which is based on the permutation–confusion–substitution structure. In our scheme, the Hamming distance is used to design a plain-related chaotic system initial condition, and the generated chaotic sequences are assigned to permutation, diffusion, and substitution stages. In the permutation stage, an effect pixel confusion is implemented through a new permutation approach, which is a double-ended select-swap scrambling strategy. In the diffusion stage, DNA XOR operation is implemented followed by DNA triploid mutation which is introduced to enhance the strength of our encryption system. A number of experiments and extensive safety analysis have been carried out and the results fully justify that our scheme not only ensures desirable security but also has superior efficiency.

Chaos-Based Fast Image Encryption Scheme with Double Zigzag Permutation and Secure SHA256

Encryption is generally used to protect the content of images. This paper proposes a simple chaos-based color image encryption algorithm with permutation and diffusion stages dependent on the plain image to increase plain text sensitivity by collaboratively leveraging a sampled random noise signal, SHA-256, Henon chaotic map, double zigzag scanning and Lorenz system. Specifically, a hash value of the plain image and a sampled true random noise signal are generated using SHA-256 hash function and considered as an initial one-time key, which is then used to locate values from the sampled true random noise signal array to define the initial values and parameters for chaotic Henon map and Lorenz system. The Henon chaotic map creates an output that defines the starting point for double zigzag pixel scanning in the permutation stage, whereas the Lorenz system generates three sequences to diffuse the image’s three components; red, green, and blue using the XOR operation in order to get an encrypted image. Finally, statistical analysis results are offered to evaluate the complexity and ascertain security functionality for the proposed algorithm. Results show that the proposed image encryption algorithm is superior in comparison to other existing algorithms.

A Secure and Lightweight Chaos Based Image Encryption Scheme

In this paper, we present an image encryption scheme based on the multi-stage chaos-based image encryption algorithm. The method works on the principle of confusion and diffusion. The proposed scheme containing both confusion and diffusion modules are highly secure and effective as compared to the existing schemes. Initially, an image (red, green, and blue components) is partitioned into blocks with an equal number of pixels. Each block is then processed with Tinkerbell Chaotic Map (TBCM) to get shuffled pixels and shuffled blocks. Composite Fractal Function (CFF) change the value of pixels of each color component (layer) to obtain a random sequence. Through the obtained random sequence, three layers of plain image are encrypted. Finally, with each encrypted layer, Brownian Particles (BP) are XORed that added an extra layer of security. The experimental tests including a number of statistical tests validated the security of the presented scheme. The results reported in the paper show that the proposed scheme has higher security and is lightweight as compared to state-of-the-art methods proposed in the literature.

A reliable chaos-based cryptography using Galois field.

Chaos-based image encryption schemes have been extensively employed over the past few years. Many issues such as the dynamical degradation of digital chaotic systems and information security have been explored, and plenty of successful solutions have also been proposed. However, the impact of finite precision in different hardware and software setups has received little attention. In this work, we have shown that the finite precision error may produce distinct cipher-images on different devices. In order to overcome this problem, we introduce an efficient cryptosystem, in which the chaotic logistic map and the Galois field theory are applied. Our approach passes in the ENT test suite and in several cyberattacks. It also presents an astonishing key space of up to 24096. Benchmark images have been effectively encrypted and decrypted using dissimilar digital devices.

Performance comparison between Chaos and quantum-chaos based image encryption techniques.

Today’s digital era has undertaken most of the responsibilities of public and private sectors, not only the industries or big organizations dependent on the internet but individual’s household needs also lying on it. To make the data transmission/reception confidential and secure for both internet users and internet service providers, a large number of researches have been done in this field. It has proved that cryptography is the best solution for solving this purpose. Mostly, digital images are continuously transferring on the network rather than texts. Enciphering a digital image is a much bulkier and a complex task. It has been evident from many types of research that chaotic logistic map-based equations provide a great level of randomness. Hence Chaotic logistic maps-based image encryption techniques (also called chaos techniques) were implemented to obtain highly random cipher images. On the other hand, time consumption must be as low as it can be possible to sustain real-time communication. Presently, the advanced encryption schemes based on quantum technology have enhanced efficiency and security because of having a large key-space and less time complexity along with randomness. The quantum-chaos based encryption is done by utilizing uncertainty principles of quantum mechanics on logistic maps. This paper is an effort to compare chaos and quantum chaos-based image encryption schemes. MATLAB 2016a software is used for the execution and the comparison is made based on various security attack analyses. Based on the study and experimental results, the quantum chaos techniques used for bit plane scrambling provides better results in terms of effectiveness, efficiency, and trustworthy that can be adopted for highly secured image encryption.

A Lightweight Chaos-Based Medical Image Encryption Scheme Using Random Shuffling and XOR Operations

Medical images possess significant importance in diagnostics when it comes to healthcare systems. These images contain confidential and sensitive information such as patients’ X-rays, ultrasounds, computed tomography scans, brain images, and magnetic resonance imaging. However, the low security of communication channels and the loopholes in storage systems of hospitals or medical centres put these images at risk of being accessed by unauthorized users who illegally exploit them for non-diagnostic purposes. In addition to improving the security of communication channels and storage systems, image encryption is a popular strategy adopted to ensure the safety of medical images against unauthorized access. In this work, we propose a lightweight cryptosystem based on Henon chaotic map, Brownian motion, and Chen’s chaotic system to encrypt medical images with elevated security. The efficiency of the proposed system is proved in terms of histogram analysis, adjacent pixels correlation analysis, contrast analysis, homogeneity analysis, energy analysis, NIST analysis, mean square error, information entropy, number of pixels changing rate, unified average changing intensity, peak to signal noise ratio and time complexity. The experimental results show that the proposed cryptosystem is a lightweight approach that can achieve the desired security level for encrypting confidential image-based patients’ information.

Chaos-based medical image encryption scheme using special nonlinear filtering function based LFSR

In this paper, a new medical image encryption system is proposed using a special nonlinear filter function based linear feedback shift register (LFSR). This special nonlinear filter function based LFSR is used as a pseudo-random number generator (PRNG). In this generator, word-based effective operation has been applied to speed up the process of encryption and decryption. Firstly, the medical image is randomized by Logistic-Tent map and scrambled by Arnold transformation method. Next, the disordered image data is XORed with output sequences of specially designed PRNG to obtain cipher image. Our designed structure aims to provide high-level randomness in the cipher image content. Encryption decryption time requirements reveal the efficiency of the proposed system. Several performance measures are estimated to validate the resistance of the proposed scheme against statistical, differential, and a few common cryptanalytic attacks. The proposed encryption scheme compares favorably with several existing image encryption schemes.

An efficient color image encryption scheme based on a matrix scrambling method and a new hybrid chaotic map

In this paper, an efficient chaos-based image encryption scheme for color images is proposed. This paper includes a strong displacement structure through a specified matrix scrambling method for pixel positions and a new hybrid chaotic map as a key generator for encryption. Chaotic Logistic map is used to generate binary bitstream for controlling diffusion process. The designed map exhibits superior performance in terms of key space range, complexity and chaotic substantiality that enhances security of the whole system. NPCR, UACI, MSE and PSNR values, which are frequently used in performance and security analysis in the field of image encryption, are at a satisfactory level and all parameters have successfully met the necessary conditions. For instance, in a good image encryption algorithm, ideal values of NPCR and UACI parameters should be 99.60% and 33.46%, respectively. The average results obtained in this study are very close to their ideal values as 99.6046 and 33.4733 for NPCR and UACI, respectively. According to a scientific study presented in the similar field, MSE value should be greater than 9,555; PSNR value must be less than 8.3875. In this study, average MSE and PSNR values calculated for six different test images are 10,315 and 7.9961, respectively. Some important analysis results have been compared to that of well-known Advanced Encryption Standard (AES) algorithm and a similar study presented in this field. Theoretical analysis and experimental results confirm that the proposed algorithm has great security and effectively encrypts and decrypts the color images with different sizes as well.

A Novel Image Encryption Scheme Based on PWLCM and Standard Map

In the past decades, considerable attention has been paid to the chaos-based image encryption schemes owing to their characteristics such as extreme sensitivity to initial conditions and parameters, pseudo-randomness, and unpredictability. However, some schemes have been proven to be insecure due to using a single chaotic system. To increase the security, this work proposes a novel image encryption scheme based on the piecewise linear chaotic map (PWLCM) and the standard map. To the best of our knowledge, it is the first chaos-based image encryption scheme combining the PWLCM with the standard map, which adopts permutation-diffusion structure. Unlike the traditional scrambling way, a hierarchical diffusion strategy, which not only changes the pixel position but also modifies the value, is employed in the permutation phase. The operation model of row-by-row and column-by-column is further used to enhance the efficiency in the diffusion process. Consequently, a good trade-off efficiency and security can be achieved. Furthermore, the numerical simulations and performance analyses illustrate that the proposed encryption scheme can be used in practical application scenarios requiring lightweight security.

A Novel Chaos-Based Image Encryption Scheme by Using Randomly DNA Encode and Plaintext Related Permutation

To ensure the security and privacy of digital image when its transmitting online or storing in the cloud, we proposed a novel chaos based image encryption scheme by using randomly DNA encode and plaintext related permutation. In our scheme, we first randomly encode plain image into a nucleotide sequence under the control by the piecewise linear chaotic map(PWLCM). After that, the plaintext related permutation would be done under the control sequence which generated by hyper chaotic Lorenz system (HCLS). Next, we make diffusion processing with key DNA sequence which is generated by another PWLCM system and also encoded randomly. Finally, we decode DNA sequence into cipher image matrix. In addition, we used many common security analysis methods to test our scheme, and the result compared with other works. The tests and comparison results are shown that our proposed image cryptosystem has excellent security performance to ensure the digital image security on communication.

A Novel Chaos-Based Color Image Encryption Scheme Using Bit-Level Permutation

To ensure the security of digital images during transmission and storage, an efficient and secure chaos-based color image encryption scheme using bit-level permutation is proposed. Our proposed image encryption algorithm belongs to symmetric cryptography. Here, we process three color components simultaneously instead of individually, and consider the correlation between them. We propose a novel bit-level permutation algorithm that contains three parts: a plain-image related rows and columns substitution, a pixel-level roll shift part, and a bit-level cyclic shift part. In the plain-related rows and columns substitution part, we involve the plain-image information to generate a control sequence by using a skew tent system. This process ensures that the correlation between three color components can be totally broken, and our cryptosystem has enough plain-image sensitivity to resist the differential attack. In the pixel-level roll shift part and bit-level cyclic shift part, we have a fully bit-level permutation controlled by two sequences using a Rucklidge system. The simulation and some common security analyses are given. Test results show that our proposed scheme has good security performance and a speed advantage compared to other works.

Cryptanalysis of two similar chaos-based image encryption schemes

Chaos based image encryption cryptosystems have garnered much attraction in the recent past. In this regard, recently, two chaos-based image encryption algorithms have been proposed. Both the cryptosystems exhibit very good cryptographic metrics. The first cryptosystem utilizes cryptographic tweaks and other cryptographic primitives to encrypt digital images. This cryptosystem also relies on the idea that a tweak can make the cryptosystem secure. Our paper points out that merely using a tweak doesn’t make the cryptosystem secure and additionally, the structure and stages in the algorithm bear inability to preserve confidentiality of sensitive data. The second cryptosystem is an enhancement of another cryptosystem. Our work indicates that the enhancement in the second cryptosystem is also weak and allows an adversary to retrieve the exact key itself. Both the cryptosystems have similar weaknesses and don’t follow the guidelines laid down by National Institute of Standards and Technology (NIST). It is observed that both the cryptosystems can be broken, to reveal the exact chaotic sequence used for encryption, using a Chosen Plaintext Attack. From this work, it is realized that the weaknesses in the methods can be partially avoided by strictly following the rules laid down by the cryptographic community and NIST. Apart from this, it is expected that future cryptosystems follow all the suggestions mentioned in our work so that, before the cryptosystem is out for attack by cryptanalysts, it is scrutinized sufficiently.

Design and Analysis of a Novel Chaos-Based Image Encryption Algorithm via Switch Control Mechanism

Chaos has been widely used in image encryption due to its rich properties. However, it remains an irreconcilable contradiction for security and implementation efficiency for image encryption schemes. In this paper, a novel chaos-based image encryption scheme has been proposed, where the Lorenz chaotic system is applied to generate pseudorandom sequences with good randomness, and a random switch control mechanism is introduced to ensure the security of the encryption scheme. Experimental results demonstrate the effectiveness and superiority of the algorithm.

A Novel Medical Image Signcryption Scheme Using TLTS and Henon Chaotic Map

In tele-medicine, images based on patient diagnostic tests and reports are usually required to broadcast securely so that recipient can receive them without any error. For the secure communication of sensitive medical data, there is a need of authenticated and unforgeable cryptosystem. In this paper, we propose a novel signcryption technique for medical images that fulfills the necessary security requirements of sensitive medical data during its communication. The design of novel medical image signcryption scheme is empowered by the combination strategy of hybrid cryptography. It employs a technique of public key cryptography furnished with elliptic curve cryptography for the generation of secret encryption key. The proposed scheme uses elliptic curve for signcryption purpose and chaotic maps for performing encryption of the medical images. It gives a combined mechanism of key exchange, digital signature and chaotic image encryption. Image encryption phase contains permutation and diffusion for pixel scrambling. The proposed image signcryption scheme provides confidentiality, authentication, integrity, unforgability, forward secrecy and non-repudiation. The use of chaos-based symmetric image encryption scheme shows good results for key space analysis, key sensitivity, correlation analysis, number of pixel change rate, unified average changing intensity, entropy analysis and histogram analysis. On the basis of the results obtained from all these analyses, we believe that the proposed medical image signcryption scheme is efficient and robust, providing good security for sensitive medical images.